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Aug. 6, 1929. A. L.. ElcHER FORGED GEAR WORM" Filed Nov a fm rarerkALBERT L. EICHER, OF CANAL FULIGN, OHIO.

FGRGED GEAR WORM.

`Original application led tTune 26, 1925, Serial No. l. Divided and thisapplication filed November 5, ieee.

The invention relates to forged worms for driving gears 1n automobilesand the like, and more particularly worms designed stresses; and this'application is a. division of my prior application for patent for animproved method of forging gear worms, filed J une 26, 1926, Serial No.118,659.

Gear worms made by a usual method of manufacturing which includesforging a cylindric blank and forming the worm threads therein bymachine cutting away all of the material between the threads, arecharacterized by the fact that, by said process of manufacture, theparticles of material are arranged in the forged cylindric blank in amanner to present the appearance of longitudinally extendingarrangements of particles as viewed upon a longitudinal plane surface ofthe blank exposed by axially and longitudinally cutting the blank intotwo semi-cylindric pieces.

After machine cutting the worm threads in such'a blank, andlongitudinally and axially cutting the worm thus formed into two halfworms, the longitudinal axial plane surface thus exposed yof one of thehalf worms still presentsthe appearance of longitudinally extendingarrangements of particles within the worm, and which are transverselysevered by the machine cutting of the worm threads in the forgedcylindric blank.

Moreover, in a gear worm machine cut from a forged cylindric blank, fromthe appearance of the sur-face exposed by longitu-V dinally and axiallycutting as aforesaid the gear worm into two half worms, the particles ofmaterial constituting the gear worm may be said to have a substantiallyuniform density throughoutv the worm.

If gear worms are made by the improved method of manufacture set forthin my prior patent, No. 1,474,516, it will be found, by longitudinallyand axially cutting worms thus made at several different angles, thatthe particles constituting the worm are not arranged in the same mannerat all longitudinal planes.

The exposed surface corresponding to an axial plane perpendicular to thetop and bottom of the preliminary dies and to the opposed die faces,presents in that plane, the

particles constituting the worm disposed in arrangements that at theouter portions of the worm are not cut through, but substantially followthe hill and valley contours of the threads.

On the other hand, in spite of the rectification by the finishing dies,of the distorted worm threads formed by the preliminary dies, it will befound by axially and longitudinally cutting' a worm made according tothe method of my foregoing patent along a plane corresponding to thehorizontal plane of the worm as it is positioned in the prelimi narydies, that is to say at right angles to the aforesaid vertical plane,that the surface thus exposed presents an arrangement of the particlesconstituting the worm at this plane which does not follow the hill andvalley contour of the threads, and a substantial number of which are cutthrough near the base of the threads.

rihis cutting through of the arrangements of particles at the base ofthe threads is unavoidable when manufacturing worms according to themethod of my aforesaid Patent No. 1,47%,516 because of the fact that thepreliminary thread dies repeatedly strike the stock positioned thereinwithout any rotating until the distorted threads are shaped on the worm,and usually with the formation of fins along each side of the worm as inthe aforesaid horizontal plane.

ln other words, it may be possible to forge worms by the method of myaforesaid patent, having arranged particles in the vertical plane of theworm as it lies between the preliminary thread forming dies followingthe hill and valley contour of the threads and not cut through by thedies; but it is impossible not to cut through the arrangements of theparticles in the horizontal plane of the worm as it lies between thepreliminary thread forming dies.

It has been found by test that whenever by any manufacturing operationsuch as machine cutting or the cutting action as distinguished from thepressing or flowing action of dies, arrangements of particles are cutthrough, the resulting product is weaker than if the arrangements of theparticles were not cut through.

Accordingly while worms forged according to the method of my priorpatent as aforesaid7 have not as many arrangements cut through as wormsmade by machine cutting a forged cyl indric blank, and are consequentlystronger, such forged worms have some arrangements cut through and are.not uniformly strong at any axial longitudinal plane.

Moreover it has been found desirable to have, in a machine element suchworms, a greater denseness of particles arranged therein near thewearing surfaces than in the central portions thereof.

Accordingly, the objects of the present improvements are to provide aworm having particles in any longitudinal axial plane thereof, arrangedfollowing the hill and valley contour of the threads, and to provide agreater denseness of the particles of the worm at and adjacent thewearing surfaces thereof than in the central portion thereof.

.From a different standpoint the objects of the present inventionincluse the provision of a worm having `helically continuously arrangedparticles rearranged from Ylongitudinally continuous locations.

These objects are attained in theproduct of the present invention, andmay be preferably made according to the improved method of forging gearworms set forth in my aforesaid application for U. S. Letters Patent,filed J une 26, 1926, Serial No. 118,- 659 of which this application adivision.

rlhe invention herein is illustrated in the accompanying drawing formingpart hereof in which Figure 1 is a longitudinal fragmentary elevation ofone of the improved gear worms having threads formed of a varyingdenseness of helically and longitudinally continuously arrangedparticles following the contour of the worm threads and having a greaterdenseness at and adjacent the wearing surfaces thereof than in vthecentral portions thereof;

F ig. 2, an enlarged fragmentary View of the surface, as it appears in aphotograph exposed upon one half of the worin of Fig. 1, bylongitudinally and axially cutting the same along any axial plane;polishing and etching the exposed surface, thereby show ing the grainstructure; and

Fig. 3, a view of the surface as it appears in a photograph exposed uponone half of a worm made by machine cutting threads in a` forgedcylindric blank, by longitudinally and axially cutting the same along anaxial lane' Jolishin' and etching the exposed surface, thereby showingthe grain structure.

Similar numerals refer to similar parts throughout the drawings.

The gear worm 10 embodying the present improvements includes the shaft11 about which worm threads 12 are spirally or helically formed or woundby the method of forging worms set forth in my prior parent applicationfor patent, Serial No. 118,659.

The particles of material constituting the worm and threads thereof arein continuous, unsevered arrangements atany plane therein.

F 2 illustrates the plane surfacecxposed upon one half of one of theimproved Vworms by longitudinally and axially cutting the saine into twohalf worms along any plane.

The particles constituting the worms are thus seen to be in continuous,unsevered `arrangen'ients which follow the contours of the worin threadsat the outer port-ions of the worm.

Likew'se it may he seen, that there is a varying denseness of particlesfollowing the contour of the threads and having a greater densencss atthe outer portions thereof adjacent the wearing surfaces of the threadsthan in the central portions thereof. I

Since the surface exposed in Fig. 2 was exposed by longitudinallycutting a worm along any longitudinal and axial plane, it also apparentthat the arrangements of particles constituting the' worm are continuousand unsevered in all directions, spil-ally or helically, as well aslongitudinally.

cutting a ong any` longitudinal and axial plane a gear worm made bymachine cutting the threads therein from a forged cylindric blankaccording to a usual and well-known method.

rlhe machine cut gear worm 2Qv of Fig. 3 includes a shaft 21 upon whichworm l threads 22 are shaped by cutting away material between thethreads.

Fig. 3 clearly illustrates that the particles constituting a machine cutgear worm are in arrangements all parallel with the longitudinal axis ofthe worm through the greater part of its length except at its endreduced by the swedging operation employed for forming the end.

These longitudinal and axial parallel ar.- rangements of particles aresevered by machine cutting away thematerial to form the threads.Likewise the particles have a substantially uniform density throughoutthe worm.

The improved gear worms 10 are stronger in any plane, than machine cutgear worms 20; and in all but one plane, than worms formed according tothe method of my prior patent, No. 1,474,516, for the reason that it isimpossible to carry out the method of my prior patent without severingthe material at the sides of the gear worm when it is being forgedwithout rotation between the preliminary sides. l

Machine cut gear worms as illustrated in Fig. 3 were tested as beamssupported at their ends, each upon two bearings six inches apart, andeach loaded at the center upon the top of the center thread. These 3illustrates the surface exposed byv Worms broke aty loads between 60,000and V70,000 pounds.y y

`forged gear worms of the present invention lies in the fact that theymay be finish swedged, either hot or cold, for further densifying theAouter particles thereof, after being subject to the operations setforth in my prior application, Serial No. 118,659, after which the Wormsmay be finish ground ready for use, Without requiring any finish machinecutting or hobbing operation.

Another advantage of the improved forged gear worms herein set forth, isthat the heat of friction generated by the pres sure of the gear Wheelagainst the gear worm when the same is in use, is carried away by thedense and continuous longitudinal and spiral arrangement of the outerparticles of the improved worms; whereas, in machine cut worms thesevered ends of the cylindric arrangements tend to retain the heat offriction.

vention are very economical of material, and require less material thanthe forged gear Worms of my prior patent, No.' 1,474,516 as aforesaid,because no fins are made during the process of manufacturing the presentgear worms.

f Obviously there is a very substantial saving in material in thepresent improved worm as compared with a machine cut gear worm.

I claim:

1. An integral gear worm including helically located thread particlesrearranged in varying denseness from a longitudinal location.

2. An integral gear worm including at any longitudinal plane avaryingdenseness of continuously arranged particles following the contour ofthe worm threads.

3. A gear worm including a greater denseness of continuously arrangedparticles adjacent the wearing surfaces thereof than in the centralportions thereof.

4. An integral gear Worm including a varying denseness of helically,continuously arranged particles forming the threads thereof.

5. An integral gear worm including a varying denseness of helicallyandlongitudinally continuouslyr arranged particles forming the threadsthereof.

6. An integral gear worm including at any plane a varying denseness ofcontinuously arranged particles forming the threads thereof.

7. An integral gear worm including a shaft and threads formed thereon,the shaft and threads including at any plane a varying denseness ofcontinuously arranged particles.

In testimony that I claim the above, I have hereunto subscribed my name.

ALBERT L. E101-IER.

